Challenges in relating land use to sediment yield in the Upper Yangtze

Observations of the spatial pattern of sediment yields within the Upper Yan gtze basin have suggested the importance of agricultural land as a major so urce area. The paper attempts to examine the relationship between land use and sediment yield by incorporating land cover types, derived from AVHRR da ta, into a multivariate analysis of factors controlling sediment yields. Th e extraction and analysis of catchment variables is undertaken in a GIS fra mework. Relationships between indices of agricultural land and sediment yie lds are highly scattered and the precise influence of land use on regional sediment yields remains rather inconclusive. There is a tendency for catchm ent areas with high proportions of arable land to exhibit high sediment yie lds but the individual catchments generating the highest sediment yields wi thin the Upper Yangtze appear to relate to specific conditions such as land sliding or loess cover.